Urea derivatives

ABSTRACT

Urea derivatives of the following formula: ##STR1## wherein R 2  indicates a piperidino or pyrrolidino group which may be substituted with a hydroxy group or a lower alkyl group having 1 to 13 carbon atoms; A indicates an ethylene group, propylene group, butylene group or butenylene group; R 2  indicates a straight or branched alkyl group having 1 to 20 carbon atoms, a benzyl group, or a phenyl group which may have 1 to 3 substituents such as a lower alkyl group having 1 to 6 carbon atoms, a lower alkoxy group having 1 to 3 carbon atoms, a halogen atom, a trifluoromethyl group, an amino group, a nitro group or a methylenedioxy group; and X indicates an oxygen or sulfur atom, as well as the hydrates and pharmaceutically acceptable salts thereof are useful antiulcer agents.

This is a continuation of application Ser. No. 222,520, filed on Jul. 21, 1988, now U.S. Pat. No. 4,952,591.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to novel urea derivatives and their medically acceptable acid addition salts having a strong gastric antisecretory activity together with a strong gastric cytoprotective activity. Thus, the compounds of this invention are useful for the treatment of peptic ulcer. This invention also relates to processes for the manufacture thereof.

It has been well-known that gastric acid secretion caused by histamine is mediated by histamine H₂ -receptor, and the blockade of this receptor by its antagonist reduces the gastric acid secretion in animals and humans (Brimblecombe, R. W., et al., J. Int. Med. Res., 3, 86-92, 1975). Several drugs of this type, such as cimetidine, are commercially available.

It has also been said that a compound which prevents or cures the gastric lesions induced by a necrotizing agent such as hydrochloric acid or absolute ethanol has gastric cytoprotective activity (Robert, A., et al., Gastroenterology, 77, 433-443. 1979). Gastric cytoprotective effect is achieved independently of the inhibitory action on gastric acid secretion. In fact, histamine H₂ -receptor antagonists hitherto known cannot suppress the formation of gastric lesions induced by absolute ethanol or 0.6N HCl.

As the similar type of the compounds of the present invention, the compounds discovered by Allen & Hanburys Limited have been known (Brit. Pat. Publication No. 1,604,674 and 1,604,675). The urea derivatives mentioned in these publications, however, have only dimethylaminomethylphenoxy group, and no mention is made on piperidinomethylphenoxy group. Furthermore, these publications mentioned only histamine H₂ -receptor antagonistic activity, but no description is made on gastric cytoprotective activity.

A number of histamine H₂ -receptor antagonists has been developed and they bring high ulcer-healing rate in clinical therapy. However, it has come to be drawn as a serious problem that the recurrence and relapse of peptic ulcer frequently occur within weeks or a few months after withdrawal of administration of histamine H₂ -receptor antagonist hitherto known. Recently, to improve this problem, a concomitant use of histamine H₂ -receptor antagonist with gastric cytoprotective agent has come to be tried in practice.

In addition, it has been well-known that antiulcer drugs having gastric cytoprotective activity are more effective for gastric ulcers than for duodenal ulcers, while histamine H₂ -receptor antagonists are more effective for duodenal ulcers than for gastric ulcers.

Therefore, it is expected that a new type of histamine H₂ -receptor antagonist having not only strong gastric antisecretory activity but also gastric cytoprotective activity can reduce the recurrence and relapse of peptic ulcer, and also improve the healing rate and healing process of peptic ulcer.

To improve the weak points of the known histamine H₂ -receptor antagonists, namely, to prevent the recurrence and relapse of peptic ulcer, we have continuously studied for development of the new type of histamine H₂ -receptor antagonists. Consequently, we have succeeded in the development of histamine H₂ -receptor antagonists having a strong gastric antisecretory activity together with a strong gastric cytoprotective activity.

The compounds of the present invention are novel urea derivatives represented by the following formula (I). ##STR2## wherein R₁ indicates a piperidino group or pyrrolidino group which may be substituted with hydroxy group or lower alkyl group having 1 to 3 carbon atoms; A indicates an ethylene group, propylene group, butylene group or butenylene group; R₂ indicates a straight or branched alkyl group having 1 to 20 carbon atoms, cycloalkyl group having 3 to 6 carbon atoms, benzyl group, or phenyl group which may have 1 to 3 substituents such as lower alkyl group having 1 to 6 carbon atoms, lower alkoxy group having 1 to 3 carbon atoms, halogen atom., trifluoromethyl group, amino group, nitro group or methylenedioxy group; X indicates an oxygen or sulfur atom, the hydrates and pharmaceutically acceptable acid addition salts thereof.

According to the invention, the compounds represented by the general formula (I) are prepared through various routes as follows.

(1) The compounds represented by the general formula (I) can be prepared by allowing the compounds of the general formula (II); ##STR3## (wherein R₁ and R₂ have the same meanings as described above) to react with isocyanate derivatives represented by the general formula (III).

    XCN--R.sub.2                                               (III)

(wherein R₂ and X have the same meanings as described above) Typically, they can be prepared by allowing isocyanate derivatives (III) to react with compounds of the general formula (II) in a suitable solvent, for example, alcohol, benzene, chloroform, dichloromethane, and so on. The reaction temperature is selected appropriately within a range of room temperature to boiling point of the solvents. At this time, the addition of a catalyst, such as triethylamine, is also preferable.

(2) The compounds represented by the general formula (Ia); ##STR4## (wherein X₁ indicates an oxygen atom and R₁, R₂ and A have the same meanings as described above)

can be prepared by allowing the compounds represented by the general formula (IV)

    H.sub.2 N--R.sub.2                                         (IV)

(wherein R₂ has the same meaning as described above)

to react with compounds of the general formula (II) in the presence of N,N'-carbonyldiimidazole. Typically, they can be prepared by the direct reaction of amines represented by the general formula (IV) with imidazolecarbonylamides, which are obtained from amines with N,N'-carbonyldiimidazole. They can be also prepared by the direct reaction of amines represented by the general formula (II) with imidazolecarbonyl amides, which are obtained from amines (IV) with N,N'-carbonyldiimidazole. There is no different either case of isolation and non-isolation of imidazolecarbonylamides. The suitable solvent of this reaction is organic solvent such as benzene, tetrahydrofuran (THF), chloroform, dichloromethane, and so on. The reaction temperature is selected appropriately within a range of room temperature to boiling point of the solvents.

(3) The compounds represented by the general formula (Ia) can be prepared by allowing the compounds of the general formula (II) to react with the compounds of the general formula (V);

    Y.sub.1 COOY.sub.2                                         (V)

(wherein Y₁ and Y₂ indicate a leaving group each independently)

and the compounds of the general formula (IV). They can be prepared by the reaction that compounds of a general formula (II) are at first converted to its urethanes in the presence of the compound of the general formula (V) and the urethanes are reacted with compounds of the general formula (IV). They can be also prepared by the reaction that compounds of the general formula (IV) are at first converted to its urethanes in the presence of the compound of the general formula (V) and the urethanes are reacted with compounds of the general formula (II). There is no different in either case of isolation and non-isolation of urethanes. The suitable solvent of this reaction is organic solvent such as benzene, THF, chloroform, dichloromethane, dimethylformamide (DMF), and so on. The reaction temperature is selected appropriately within a range of room temperature to boiling point of the solvents. At this time, the addition of the catalysts such as pyridine, triethylamine, and so on, is also preferable. In this case, it is desirable that leaving group Y₁ of the compound represented by the general formula (V) is halogen atom for example, chlorine or bromine atom and leaving group Y₂ is lower alkyl group.

(4) The compounds represented by the general formula (I) can be prepared by allowing phenol derivatives represented by the general formula (VI); ##STR5## (wherein R₁ has the same meaning as described above) to react with compounds represented by the general formula (VII). ##STR6## wherein Y₃ indicates a leaving group and R₂, A and X have the same meanings as described above)

The suitable solvent of this reaction is organic solvent such as methanol, ethanol, propanol, isopropanol, 3-methoxypropanol, and so on. The reaction temperature is selected appropriately within a range of 0° C. to boiling point of the solvents. At this time, the addition of the catalysts such as basic catalyst, for example, sodium, sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, and so on, is also preferable. In this case, it is also desirable that leaving group Y₁ of the compound represented by the general formula (VII) is halogen atom for example, chlorine or bromine atom.

(5) The compounds represented by the general formula (I) can be prepared by allowing the compounds represented by the general formula (VIII) ##STR7## (wherein R₁, A and X have the same meanings as described above)

to react with the compounds represented by the general formula (IV). The suitable solvent of this reaction is organic solvent such as ethanol, benzene, chloroform, dichloromethane, THF, DMF, and so on. The reaction temperature is selected appropriately within a range of room temperature to boiling point of the solvents. At this time, the addition of the catalyst, such as triethylamine, and so on, is also preferable.

(6) The compounds represented by the general formula (Ic); ##STR8## (wherein R₃ indicates an aminophenyl group and R₁, A and X have the same meanings as described above)

can be prepared by hydrogenation of the compounds represented by the general formula (Ib). ##STR9## (wherein R₄ indicates a nitrophenyl group and R₁, A and X have the same meanings as described above)

This reduction is accomplished by the reaction with metal such as, for example, iron, tin, and so on, in the presence of acid, such as, hydrochloric acid, acetic acid, and so on, in the suitable organic solvent, such as, ethanol, isopropanol, dioxane, and so on. The reaction temperature is selected appropriately within a range of room temperature to boiling point of the solvents. This reduction is also accomplished by the catalytic hydrogenation using palladium on chacoal, and so on, in the inert solvent such as, ethanol, isopropanol, 3-methoxybutanol, dioxane, DMF, and so on. The temperature is selected appropriately within a range of room temperature to boiling point of the solvents.

Furthermore, the compounds represented by the formula (I) can be converted to the medically acceptable acid addition salts by treatment with acid as usual manner. The acid may be inorganic acid such as, hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, and so on, or organic acid such as, acetic acid, propionic acid, citric acid, lactic acid, maleic acid, fumaric acid, succinic acid, tartaric acid, methanesulfonic acid, and so on.

The following examples will further illustrate the present invention without, however, limiting it thereto.

EXAMPLE 1 N-(4-Methoxyphenyl)-N'-[3-(3-piperidinomethylphenoxy)propyl]urea

To the mixture of 3-(3-piperidinomethylphenoxy)propylamine (3.1 g) in ethanol (31 ml) was added 4-methoxyphenylisocyanate (1.9 g) dropwise slowly under cooling on an ice-water bath. The reaction mixture was stirred at room temperature for 2.5 hours and then concentrated under reduced pressure. The resulting residue was dissolved in dichloromethane (50 ml), washed with diluted hydrochloric acid, saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution successively and dried over anhydrous magnesium sulfate. After removal of the solvent under reduced pressure, the crude product (3.3 g) was obtained (yield 66.0%). This crude product was recrystallized from ethanol to give the title compound (2.1 g), mp 111-112° C.

Analysis (%) for C₂₃ H₃₁ N₃ O₃, Calcd. (Found): C, 69.49 (69.28); H, 7.86 (7.86); N, 10.57 (10.54).

EXAMPLE 2-50

The analytical data of the compounds of Example 2-50, synthesized as same manner as the process of Example 1, are summarized in Table 1 (1) to (4).

                                      TABLE 1                                      __________________________________________________________________________                                                          Analysis                                                                             Calcd.              Ex.                                          Molecular                                                                              (%)   Found               No.                                                                               R.sub.1    A           X R.sub.2     mp (°C.)                                                                     formula C  H  N                   __________________________________________________________________________      2                                                                                 ##STR10## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR11##  109-111                                                                             C.sub.22 H.sub.29 N.sub.3                                                      O.sub.2 71.90 71.94                                                                       7.95 8.00                                                                         11.43 11.39          3                                                                                 ##STR12## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR13##  103-105                                                                             C.sub.23 H.sub.31 N.sub.3                                                      O.sub.2 72.41 72.31                                                                       8.19 8.15                                                                         11.01 10.92          4                                                                                 ##STR14## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR15##  114-116                                                                             C.sub.23 H.sub.28 F.sub.3                                                      N.sub. 3 O.sub.2                                                                       63.43 63.41                                                                       6.48 6.50                                                                         9.65 9.58            5                                                                                 ##STR16## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR17##  oily C.sub.23 H.sub.28 F.sub.3                                                      N.sub.3 O.sub.2                                                                        Mass: 435 (M.sup.+)        6                                                                                 ##STR18## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR19##  131-133                                                                             C.sub.22 H.sub.28 ClN.sub.3                                                    O.sub.2 65.74 65.76                                                                       7.02 6.94                                                                         10.45 10.49          7                                                                                 ##STR20## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR21##  58-61                                                                               C.sub.22 H.sub.28 ClN.sub.3                                                    O.sub.2 Mass: 402 (M.sup.+)        8                                                                                 ##STR22## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH.sub.2 CH.sub.2 CH.sub.3                                                                 99-101                                                                              C.sub.19 H.sub.31 N.sub.3                                                      O.sub.2 68.43 68.40                                                                       9.37 9.38                                                                         12.60 12.61          9                                                                                 ##STR23## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR24##  109-112                                                                             C.sub.23 H.sub.31 N.sub.3                                                      O.sub.2 72.41 72.47                                                                       8.19 8.18                                                                         11.01 10.98         10                                                                                 ##STR25## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR26##  92-94                                                                               C.sub.23 H.sub.31 N.sub.3                                                      O.sub.3 69.49 69.61                                                                       7.86 7.87                                                                         10.57 10.54         11                                                                                 ##STR27## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR28##  80-83                                                                               C.sub.24 H.sub.33 N.sub.3                                                      O.sub.4 67.42 67.34                                                                       7.78 7.74                                                                         9.83 9.83           12                                                                                 ##STR29## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR30##  95-98                                                                               C.sub.24 H.sub.33 N.sub.3                                                      O.sub.4 67.42 67.28                                                                       7.78 7.73                                                                         9.83 9.81           13                                                                                 ##STR31## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR32##  114-118                                                                             C.sub.23 H.sub.31 N.sub.3                                                      O.sub.3 61.12 61.33.2                                                                     7.58 7.36                                                                         9.30 9.30           14                                                                                 ##STR33## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR34##  64-66                                                                               C.sub.22 H.sub. 28 N.sub.4                                                     O.sub.4 Mass: 412 (M.sup.+)       15                                                                                 ##STR35## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR36##  oily C.sub.22 H.sub.28 N.sub.4                                                      O.sub.4 62.69 62.892                                                                      6.93 6.81                                                                         13.29 13.31         16                                                                                 ##STR37## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH.sub.2 CH.sub.3                                                                          80-81.5                                                                             C.sub.18 H.sub.29 N.sub.3                                                      O.sub.2 67.68 67.61                                                                       9.15 9.13                                                                         13.15 13.12         17                                                                                 ##STR38## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH.sub.2 CH.sub.2 CH.sub.3                                                                 88-91                                                                               C.sub.20 H.sub.33 N.sub.3                                                      O.sub.2 69.13 69.18                                                                       9.57 9.57                                                                         12.09 12.12         18                                                                                 ##STR39## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O (CH.sub.2).sub.17 CH.sub.3                                                                 100-102                                                                             C.sub.34 H.sub.61 N.sub.3                                                      O.sub.2 75.09 75.19                                                                       11.31 11.33                                                                       7.73 7.75           19                                                                                 ##STR40## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR41##  94-96                                                                               C.sub.22 H.sub.35 N.sub.3                                                      O.sub.2 70.74 70.91                                                                       9.44 9.45                                                                         11.25 11.30         20                                                                                 ##STR42## CH.sub.2 CH.sub.2 CH.sub.2                                                                 S                                                                                 ##STR43##  114-116                                                                             C.sub.23 H.sub.31 N.sub.3                                                      O.sub.2 S                                                                              66.80 66.60                                                                       7.56 7.60                                                                         10.16 10.05         21                                                                                 ##STR44## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH.sub.3    73-75                                                                               C.sub.17 H.sub.27 N.sub.3                                                      O.sub.2 66.85 66.81                                                                       8.91 8.82                                                                         13.76 13.69         22                                                                                 ##STR45## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O C(CH.sub.3).sub.3                                                                          94-95                                                                               C.sub.20 H.sub.33 N.sub.3                                                      O.sub.2 69.13 69.24                                                                       9.57 9.59                                                                         12.09 12.12         23                                                                                 ##STR46## CH.sub.2 CH.sub.2 CH.sub.2                                                                 S CH.sub.2 CH.sub.2 CH.sub.3                                                                 126-130                                                                             C.sub.19 H.sub.31 N.sub.3 OS                                                   Cl      59.12 59.14                                                                       8.36 8.35                                                                         10.89 10.93         24                                                                                 ##STR47## CH.sub.2 CH.sub.2 CH.sub.2                                                                 S                                                                                 ##STR48##  69-71                                                                               C.sub.20 H.sub.33 N.sub.3                                                              66.07 66.13                                                                       9.15 9.15                                                                         11.56 11.57         25                                                                                 ##STR49## (CH.sub.2).sub.4                                                                           O                                                                                 ##STR50##  90-91                                                                               C.sub.23 H.sub.31 N.sub.3                                                      O.sub.2 Mass: 397 (M.sup.+)       26                                                                                 ##STR51## (CH.sub.2).sub.4                                                                           O CH.sub.2 CH.sub.2 CH.sub.3                                                                 73-74.5                                                                             C.sub.19 H.sub.31 N.sub.3                                                      O.sub.2 68.43 68.05                                                                       9.37 9.30                                                                         12.60 12.56         27                                                                                 ##STR52## CH.sub.2 CH.sub.2 CH.sub.2                                                                 S                                                                                 ##STR53##  107-108                                                                             C.sub.23 H.sub.31 N.sub.3                                                              66.80 66.60                                                                       7.56 7.60                                                                         10.16 10.05         28                                                                                 ##STR54## CH.sub.2 CHCHCH.sub.2 trans                                                                O CH.sub.3    91-94                                                                               C.sub.18 H.sub.27 N.sub.3                                                      O.sub.2 68.11 67.83                                                                       8.57 8.70                                                                         13.24  13.07        29                                                                                 ##STR55## CH.sub.2 CHCHCH.sub.2 cis                                                                  O CH.sub.3    65-67                                                                               C.sub.18 H.sub.27 N.sub.3                                                      O.sub.2 68.11 68.09                                                                       8.57 8.66                                                                         13.24 13.20         30                                                                                 ##STR56## CH.sub.2 CHCHCH.sub.2  trans                                                               O CH.sub.2 CH.sub.3                                                                          66-69                                                                               C.sub.19 H.sub.29 N.sub.3                                                      O.sub.2 68.85 68.45                                                                       8.82 8.92                                                                         12.68 12.40         31                                                                                 ##STR57## CH.sub.2 CHCHCH.sub.2 cis                                                                  O CH.sub.2 CH.sub.3                                                                          72-74                                                                               C.sub.19 H.sub.29 N.sub.3                                                      O.sub.2 68.85 68.85                                                                       8.82 8.88                                                                         12.68 12.62         32                                                                                 ##STR58## CH.sub.2 CHCHCH.sub.2 trans                                                                O CH.sub.2 CH.sub.2 CH.sub.3                                                                 87-89                                                                               C.sub.20 H.sub.31 N.sub.3                                                      O.sub.2 69.53 69.70                                                                       9.04 9.10                                                                         12.16 12.17         33                                                                                 ##STR59## CH.sub.2 CHCHCH.sub.2 cis                                                                  O CH.sub.2 CH.sub.2 CH.sub.3                                                                 70-73                                                                               C.sub.20 H.sub.31 N.sub.3                                                      O.sub.2 Mass: 345 (M.sup.+)       34                                                                                 ##STR60## CH.sub.2 CHCHCH.sub.2 trans                                                                O C(CH.sub.3).sub.3                                                                          100-102                                                                             C.sub.21 H.sub.33 N.sub.3                                                      O.sub.2 70.16 70.23                                                                       9.25 9.15                                                                         11.69 11.70         35                                                                                 ##STR61## CH.sub.2 CHCHCH.sub.2 trans                                                                O                                                                                 ##STR62##  101-103                                                                             C.sub.24 H.sub.31 N.sub.3                                                      O.sub.3 70.39 70.11                                                                       7.63 7.61                                                                         10.26 10.23         36                                                                                 ##STR63## CH.sub.2 CHCHCH.sub.2 cis                                                                  O                                                                                 ##STR64##  88-90                                                                               C.sub.24 H.sub.31 N.sub.3                                                      O.sub.3 70.39 70.44                                                                       7.63 7.67                                                                         10.26 10.23         37                                                                                 ##STR65## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH.sub.3    106-108                                                                             C.sub.17 H.sub.27 N.sub.3                                                      O.sub.3  63.53 63.47                                                                      8.47 8.49                                                                         13.07 13.00         38                                                                                 ##STR66## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH.sub.3    73-76                                                                               C.sub.18 H.sub.29 N.sub.3                                                      O.sub.2 Mass: 319 (M.sup.+)       39                                                                                 ##STR67## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH(CH.sub.3).sub.2                                                                         114-117                                                                             C.sub.19 H.sub.31 N.sub.3                                                      O.sub.3 65.30 65.27                                                                       8.94 8.94                                                                         12.02 12.07         40                                                                                 ##STR68## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH(CH.sub.3).sub.2                                                                         92-95                                                                               C.sub.20 H.sub.33 N.sub.3                                                      O.sub.2 Mass: 347 (M.sup.+                                                             )                         41                                                                                 ##STR69## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH.sub.2 CH.sub.2 CH.sub.3                                                                 83-85                                                                               C.sub.20 H.sub.33 N.sub.3                                                      O.sub.2 Mass: 347 (M.sup.+)       42                                                                                 ##STR70## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH.sub.2 CH.sub.3                                                                          61-64                                                                               C.sub.19 H.sub.31 N.sub.3                                                      O.sub.2 Mass: 333 (M.sup.+)       43                                                                                 ##STR71## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O CH.sub.2 CH.sub.3                                                                          81-83                                                                               C.sub.18 H.sub.29 N.sub.3                                                      O.sub.3 Mass: 335 (M.sup.+)       44                                                                                 ##STR72## CH.sub.2 CH.sub.2 CH.sub.2                                                                 O                                                                                 ##STR73##  126-128                                                                             C.sub.23 H.sub.31 N.sub.3                                                      O.sub.4 66.81 66.79                                                                       7.56 7.58                                                                         10.16 10.10         45                                                                                 ##STR74## (CH.sub.2).sub.4                                                                           O CH.sub.2 CH.sub.3                                                                          57-58                                                                               C.sub.19 H.sub.31 N.sub.3                                                      O.sub.2 Mass: 333 (M.sup.+)       46                                                                                 ##STR75## (CH.sub.2).sub.4                                                                           O CH.sub.2 CH.sub.2 CH.sub.3                                                                 87-88                                                                               C.sub.20 H.sub.33 N.sub.3                                                      O.sub.2 Mass: 347 (M.sup.+)       47                                                                                 ##STR76## (CH.sub.2).sub.4                                                                           O CH(CH.sub.3).sub.2                                                                         54-57                                                                               C.sub.20 H.sub.33 N.sub.3                                                      O.sub.2 Mass: 347 (M.sup.+)       48                                                                                 ##STR77## (CH.sub.2).sub.4                                                                           O CH.sub.3    52-53.5                                                                             C.sub.18 H.sub.29 N.sub.3                                                      O.sub.2 Mass: 319 (M.sup.+)       49                                                                                 ##STR78## (CH.sub.2).sub.2                                                                           O CH.sub.2 CH.sub.3                                                                          oily C.sub.17 H.sub.27 N.sub.3                                                      O.sub.2 Mass: 305 (M.sup.+)       50                                                                                 ##STR79## (CH.sub.2).sub.2                                                                           O CH.sub.2 CH.sub.2 CH.sub.3                                                                 65-66                                                                               C.sub.18 H.sub.29 N.sub.3                                                      O.sub.2 Mass: 319                 __________________________________________________________________________                                                          (M.sup.+)            

EXAMPLE 51 N-(4-Ethoxyphenyl)-N'-[3-(3-piperidinomethylphenoxy)propyl]urea

(1) To the mixture of 4-phenetidine (4.6 g) and triethylamine (3.4 g) in dichloromethane (46 ml) was added ethyl chlorocarbonate (3.6 g) dropwise under cooling on an ice-water bath and the reaction mixture was stirred at room temperature for an hour. The reaction mixture was washed with water, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The resulting precipitate was suspended in petroleum ether and collected by filtration to give ethyl N-(4-ethoxyphenylcarbamate (4.0 g; yield 56.9%), mp 90-92° C.

(2) The mixture of 3-(3-piperidinomethylphenoxy)propylamine (4.7 g) and ethyl N-(4-ethoxyphenyl)carbamate (4.0 g) in 3-methoxy-2-butanol (20 ml) was refluxed for 6 hours and then concentrated under reduced pressure. The resulting residue was dissolved in dichloromethane, washed with water, diluted hydrochloric acid solution, saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution successively and dried over magnesium sulfate. After removal of the solvent under reduced pressure, the resulting residue was purified by silica gel flash column chromatography to give the precipitate (0.9 g; yield 11.4%). This precipitate was recrystallized from ethanol to give the title compound (0.5 g), mp 109-111° C.

Analysis (%) for C₂₄ H₃₃ N₃ O₃, Calcd. (Found): C, 70.04 (70.18); H, 8.08 (8.06); N, 10.21 (10.20).

EXAMPLE 52 N-(3,4-Methylenedioxyphenyl)-N'-[3-(3-piperidinomethylphenoxy)propyl]urea

To the solution of N,N'-carbonyldiimidazole (4.0 g) in dichloromethane (60 ml) was added the solution of 3,4-methylenedioxyaniline (3.4 g) in dichloromethane (20 ml) dropwise at 0-5° C. The mixture was stirred at the same temperature for an hour and then stirred at room temperature for an hour. To the mixture was further added the solution of 3-(3-piperidinomethylphenoxy)propylamine (6.1 g) in dichloromethane (30 ml) at 0° C. The reaction mixture was stirred at the same temperature for an hour and then stirred at room temperature for an hour. To the reaction mixture was added water (60 ml). The organic layer was separated and dried over anhydrous magnesium sulfate. After removal of the solvent under reduced pressure, the resulting residue was suspended in ether and collected by filtration to give the crude product (6.7 g; yield 67.0%). This product was recrystallized from ethanol to give the title compound (5.0 g), mp 128-130° C.

Analysis (%) for C₂₃ H₂₉ N₃ O₄, Calcd. (Found): C, 67.13 (67.13); H, 7.10 (7.08); N, 10.21 (10.17).

EXAMPLE 53-60

The analytical data of the compounds of Example 53-60, synthesized as same manner as the process of Example 52, are summarized in Table 2.

                                      TABLE 2                                      __________________________________________________________________________                                                         Analysis                                                                              Calcd.              Ex.                                       Molecular (%)    Found               No.                                                                               R.sub.1                                                                               A            X R.sub.2    mp (°C.)                                                                      formula   C   H  N                   __________________________________________________________________________     53                                                                                 ##STR80##                                                                            CH.sub.2 CH.sub.2 CH.sub.2                                                                  O                                                                                 ##STR81## 109-111                                                                              C.sub.24 H.sub.33 N.sub.3                                                      O.sub.3   70.04 70.02                                                                        8.08 8.08                                                                         10.21 10.21         54                                                                                 ##STR82##                                                                            CH.sub.2 CH.sub.2 CH.sub.2                                                                  O CH(CH.sub.3).sub.2                                                                        93-95 C.sub.19 H.sub.31 N.sub.3                                                      O.sub.2   68.43 68.38                                                                        9.37 9.37                                                                         12.60  12.60        55                                                                                 ##STR83##                                                                            CH.sub.2 CH.sub.2 CH.sub.2                                                                  O                                                                                 ##STR84## 68-71 C.sub.20 H.sub.33 N.sub.3                                                      O.sub.2.HCl                                                                              Mass: 347 (M.sup.+)        56                                                                                 ##STR85##                                                                            CH.sub.2 CH.sub.2 CH.sub.2                                                                  O                                                                                 ##STR86## 68-71 C.sub.20 H.sub.33 N.sub.3                                                      O.sub.2   Mass: 347 (M.sup.+)        57                                                                                 ##STR87##                                                                            CH.sub.2 CH.sub.2 CH.sub.2                                                                  O                                                                                 ##STR88## 75-77 C.sub.19 H.sub.29 N.sub.3                                                      O.sub.2   Mass: 331 (M.sup.+)        58                                                                                 ##STR89##                                                                            CH.sub.2 CHCHCH.sub.2 trans                                                                 O CH(CH.sub.3).sub.2                                                                        84-86 C.sub.20 H.sub.31 N.sub.3                                                      O.sub.2   69.53 69.34                                                                        9.04 9.11                                                                         12.16 12.15         59                                                                                 ##STR90##                                                                            CH.sub.2 CHCHCH.sub.2 trans                                                                 O                                                                                 ##STR91## 75-77 C.sub.20 H.sub.29 N.sub.3                                                      O.sub.2   69.94 69.82                                                                        8.51 8.63                                                                         12.33 12.19         60                                                                                 ##STR92##                                                                            CH.sub.2 CHCHCH.sub.2 trans                                                                 O                                                                                 ##STR93## 117-119                                                                              C.sub.25 H.sub.33 N.sub.3                                                      O.sub.3   70.89 70.65                                                                        7.85 7.77                                                                         9.92 9.82           __________________________________________________________________________

EXAMPLE 61 N-(3-Aminophenyl)-N'-[3-(3-piperidinomethylphenoxy)propyl]urea

To the mixture of N-(3-nitrophenyl)-N'-[3-(3-piperidinomethylphenoxy)propyl]urea (4.6 g) in ethanol (46 ml) was added tin (2.6 g). To the reaction mixture was added concentrated hydrochloric acid (1.9 ml) at room temperature under stirring, further added concentrated hydrochloric acid (18.2 ml) under heating on a water bath. The reaction mixture was refluxed for 6 hours, concentrated under reduced pressure, diluted with water (100 ml), alkalized with aqueous sodium hydroxide solution and extracted with dichloromethane (200 ml). The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give the crude precipitate (3.8 g; yield 88.4%). This precipitate was recrystallized two times from ethanol to give the title compound (1.8 g), mp 116-118° C.

Analysis (%) for C₂₂ H₃₀ N₄ O₂, Calcd. (Found): C, 69.08 (68.91); H, 7.91 (7.90); N, 14.65 (14.54).

EXAMPLE 62 N-Methyl-N'-[3-(3-piperidinomethylphenoxy)propyl]urea

To DMF (10 ml) was added sodium hydride (0.7 g; 60% in oil) portionwise under cooling, further added the mixture of 3-piperidinophenol (3.3 g) in DMF (7 ml) dropwise and stirred at room temperature for an hour. To the reaction mixture was added N-(3-chloropropyl)-N'-methylurea (2.6 g) at room temperature and stirred for 3 hours at the same temperature. The reaction mixture was poured into water and extracted with dichloromethane. The organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The resulting residue was suspended in petroleum ether and collected by filtration to give the crude precipitate (2.8 g, yield 52.8%). This precipitate was recrystallized from ethyl acetate to give the title compound (0.5 g).

Thus obtained compound was identified with the compound described in example 21 by comparison of analytical data.

EXAMPLE 63

The analytical data of the compound of Example 63, synthesized as same manner as the process of Example 62, is summarized in Table 3.

                                      TABLE 3                                      __________________________________________________________________________                                                         Analysis                                                                              Calcd.              Ex.                                         Molecular                                                                              (%)    Found               No.                                                                               R.sub.1    A         X  R.sub.2    mp (°C.)                                                                      formula C   H  N                   __________________________________________________________________________     63                                                                                 ##STR94## CH.sub.2 CH.sub.2 CH.sub.2                                                               O                                                                                  ##STR95## 142-144                                                                              C.sub.24 H.sub.33 N.sub.3                                                      O.sub.4 67.42 67.23                                                                        7.78 7.86                                                                         9.83 9.74           __________________________________________________________________________

EXAMPLE 64 N-Ethyl-N'-[3-(3-piperidinomethylphenoxy)propyl]urea

To DMF (5 ml) was added sodium hydride (0.5 g; 60% in oil) portionwise under cooling, further added the mixture of 3-piperidinophenol (2.3 g) in DMF (7 ml) dropwise and stirred at room temperature for an hour. To the reaction mixture was added N-(3-chloropropyl)-N'-methylurea (2.0 g) at room temperature, stirred for 3 hours at the same temperature and allowed to stand for overnight. The reaction mixture was poured into ice-water and extracted with dichloromethane. The organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The resulting residue was crystallized from petroleum ether, collected by filtration to give the title compound (0.6 g). The filtrate was concentrated and purified by silica gel column chromatography (eluting with acetone) to give the further title compound (0.8 g).

Thus obtained compound was identified with the compound described in example 16 by comparison of analytical data.

The compounds of this invention are histamine H₂ -receptor antagonists with both strong gastric antisecretory and gastric cytoprotection as shown by following experiments.

EXPERIMENT 1 Gastric antisecretion

Male Donryu rats, weighing about 200 g, were fasted for 24 hours before the experiment. Under urethane anesthesia (1.25 g/kg,i.p.), the abdomen was incised and the pylorus was ligated. The gastric cannula was implanted in the forestomach (Acute fistula method). Gastric secretion from cannula was collected into test tubes every one hour and the acid output was titrated. Histamine (10 mg/kg) was intramuscularly given after the first collection of gastric juice. Drugs were intraduodenally given after the second collection of the gastric juice. The results are shown in Table 4.

                  TABLE 4                                                          ______________________________________                                         Example     Dose (mg/kg, i. d.)                                                                          Inhibition (%)                                       ______________________________________                                          1          12.5          70.7                                                             25            98.5                                                  8          1             49.5                                                             3             77.5                                                             6             81.3                                                 16          5             49.5                                                             10            77.2                                                 29          3             39.1                                                             5             80.8                                                 51          1             29.0                                                             6             52.7                                                             25            97.1                                                 54          2             16.1                                                             5             68.2                                                             10            78.8                                                 Cimetidine  12.5          51.9                                                             25            80.0                                                             50            100.0                                                ______________________________________                                    

EXPERIMENT 2 Histamine H₂ -receptor antagonism

Male Hartley guinea-pigs, weighing between 300 and 400 g, were used in the experiment. The right atrium was dissected and suspended at 0.5 g tension in a 10 ml organ bath containing Krebs-Henseleit's solution, kept at 32±1° C. and bubbled with the gas mixture (95% O₂ and 5% CO₂). Contractions were recorded with a force-displacement transducer through a strain gange. Cumulative concentration-response curves for the positive chronotropic effect of histamine on atrium were displaced to the right in parallel by drugs, and the effects of test drugs were calculated as the pA₂ values. Drugs were added into the organ bath 5 minutes before histamine treatment. The results are shown in Table 5.

                  TABLE 5                                                          ______________________________________                                                Example pA.sub.2                                                        ______________________________________                                                 1      6.58                                                                    8      7.38                                                                   16      7.18                                                                   29      7.45                                                                   51      6.60                                                                   54      7.56                                                                   Cimetidine                                                                             6.58                                                            ______________________________________                                    

EXPERIMENT 3 Gastric cytoprotection (0.6N HCl-induced gastric lesions)

Male Donryu rats, weighing about 200 g. were deprived of food and water for 24 hours. One ml of 0.6 N HCl solution was given orally and the animals were killed an hour later. The stomach of each animal was removed and fixed 0.5% neutral formalin solution according to the method of Brodie and Hanson (Gastroenterology 38, 353-360, 1960). The length (mm) of each gastric lesion was measured under a dissecting microscope, summed, and used as an index for evaluation. Drugs were orally given an hour before 0.6N HCl solution treatment. The results are shown in Table 6.

                  TABLE 6                                                          ______________________________________                                         Example     Dose (mg/kg, p. o.)                                                                          Inhibition (%)                                       ______________________________________                                          1          25            30.1                                                             50            45.1                                                             100           67.4                                                  8           1            26.4                                                              6            55.4                                                             16            67.4                                                 16           6            52.6                                                             25            78.0                                                             50            89.4                                                 29           5            49.3                                                             25            73.8                                                 51          50            63.4                                                 54           6            36.1                                                             25            73.0                                                             50            70.1                                                 Cimetidine  100           22.0                                                 ______________________________________                                    

These data suggest that the compounds of this invention are histamine H₂ -receptor antagonists with both strong gastric anti-secretion and gastric cytoprotection. Furthermore, their gastric antisecretion were more potent than that of cimetidine. That is, the compounds of this invention may process more potent antiulcer activity for the treatment of peptic ulcer in clinical therapy. 

What is claimed is:
 1. A urea compound of the formula (I): ##STR96## wherein R₁ indicates a piperidino group or pyrrolidino group which may be substituted with a hydroxy group or a lower alkyl group having 1 to 3 carbon atoms; A indicates an ethylene, propylene, butylene or butenylene group; R₂ indicates a straight or branched alkyl group having from 1 to 20 carbon atoms; or the hydrates or a pharmaceutically acceptable acid addition salt thereof.
 2. The compound according to claim 1, which is N-ethyl-N'-[3-(3-piperidinomethyl]phenoxy)propyl]urea.
 3. The compound according to claim 1, which is N-ethyl-N'-[4-(3-piperidinomethylphenoxy)-2-butenyl]urea.
 4. An anti-ulcer pharmaceutical composition containing a therapeutically effective amount of the compound of formula (I): ##STR97## wherein R₁ indicates a piperidino group or pyrrolidino group which may be substituted with a hydroxy group or a lower alkyl group having 1 to 3 carbon atoms; A indicates an ethylene, propylene, butylene or butenylene group; R₂ indicates a straight or branched alkyl group having from 1 to 20 carbon atoms; the hydrate or a pharmaceutically acceptable acid addition salt thereof; and an inert pharmaceutically acceptable carrier.
 5. The compound according to claim 1, wherein R₁ is a piperidino group.
 6. The compound according to claim 1, wherein R₁ is a pyrrolidino group.
 7. The composition of claim 4, wherein R₁ is a piperidino group.
 8. The composition of claim 4, wherein R₁ is a pyrrolidino group. 